fee-noe-BAR-bi-tal
Therapeutic Classification: anticonvulsants, sedative/hypnotics
Pharmacologic Classification: barbiturates
BEERS REMS
Absorption: Absorption is slow but relatively complete (70–90%).
Distribution: Unknown.
Half-Life: Neonates: 1.8–8.3 days; Infants: 0.8–5.5 days; Children: 1.5–3 days; Adults: 2–6 days.
| ROUTE | ONSET | PEAK | DURATION |
|---|---|---|---|
| PO | 30–60 min | unknown | >6 hr |
| IM, SUBQ | 10–30 min | unknown | 4–6 hr |
| IV | 5 min | 30 min | 4–6 hr |
‡Full anticonvulsant effects occur after 2–3 wk of chronic dosing unless a loading dose has been used.
Contraindicated in:
Use Cautiously in:
CV: IVhypotension
Derm: DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), photosensitivity, rash, STEVENS-JOHNSON SYNDROME (SJS), TOXIC EPIDERMAL NECROLYSIS (TEN), urticaria
GI: constipation, diarrhea, nausea, vomiting
Local: phlebitis
MS: arthralgia, myalgia
Neuro: hangover, delirium, depression, drowsiness, excitation, lethargy, neuralgia, vertigo
Resp: respiratory depression, IVLARYNGOSPASM, bronchospasm
Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANGIOEDEMA AND SERUM SICKNESS), physical dependence, psychological dependence
Drug-drug:
Use with opioid analgesics may result in significant sedation, respiratory depression, coma, and death. Reserve concurrent use of these drugs for patients when alternative treatment options are inadequate; if concurrent use necessary, limit doses and durations to the minimum required.
Drug-Natural Products:
Maintenance Anticonvulsant
Sedation
Hypnotic
Hyperbilirubinemia
Prolonged therapy may lead to psychological or physical dependence. Restrict amount of drug available to patient, especially if depressed, suicidal, or with a history of addiction.
Lab Test Considerations:
Toxicity and Overdose:
IV Administration:
IV phenobarbital is a vesicant. Administer into a large vein. If extravasation occurs, immediately stop infusion. Leave needle/cannula in place temporarily but do not flush the line. Gently aspirate extravasated solution; then remove needle/cannula. Elevate patient's extremity and apply dry warm compresses. Initiate hyaluronidase antidote for refractory cases in addition to supportive management. For hyaluronidase, inject a total of 1 mL (15 units/mL) intradermally or SUBQ as five separate 0.2-mL injections (using a tuberculin syringe) around the site of extravasation; if IV catheter remains in place, administer IV through the infiltrated catheter; may repeat in 30–60 min if no resolution.
Advise patient on prolonged therapy not to discontinue medication without consulting health care provider. Abrupt withdrawal may precipitate seizures or status epilepticus.
NDC Code